This invention relates generally to an article of manufacture and process of using such article to shield the electronic noise or radiation emanating from electronic circuitry.
In applications where complex electronic circuits are utilized, the electronic noise generated by such circuits, i.e. the radio frequency/electromagnetic interference, may be of such a level as to be hazardous to nearby personnel or other electronic circuits. If such electronic noise reaches a high level, a unit may be judged unsafe by such governmental agencies as the Federal Communications Commission and be required to be recalled and redesigned by the manufacturer. It is apparent that such a recall will have a serious adverse effect on product sales.
One solution to the above problem, which has proven to be very costly to electronic circuit manufacturers, has been the redesign of circuit components to reduce RFI and EMI to acceptable levels. It has also been realized in the art that a foil shield, placed around the electronic circuitry and connected to ground, would be another effective means of reducing environmental radiation from electronic circuitry. Typically, an aluminum or copper foil is adhesively coated on both sides and an outer wrapping layer of polyester or plastics material is applied thereto.
Such aluminum and copper foil shielding uses, while somewhat effective, have proven to be somewhat costly to manufacture and, at least to some extent, not sufficiently durable for their intended use.
Accordingly, it is an object of the present invention to produce an RFI/EMI shielding device which is highly durable in the conditions of high temperature, humidity, salt and physical abuse present in many commercial applications.
It is a further object to produce an electromagnetic radiation shielding device which has enhanced conductive properties to more effectively direct the shielded radiation to electrical ground.
It is a further object to produce such a shielding device using a process which is less labor intensive, thus resulting in a shield product which may be sold at competitive commerical prices.
It is a still further object to produce an electrical interference shielding apparatus wherein the central shielding conductive layer cannot be separated from its protective plastics base layer, a condition which results in reduced performance of the apparatus. Such is accomplished by means of the novel process of the invention.
These and further objects and advantages of the present invention will become apparant as the following description proceeds, and the features of novelty characterizing the invention will be pointed out with particularity in the claims annexed to and forming a part of this specification.